Multi ply paper machine

ABSTRACT

A MULTI-PLY PAPER MACHINE UTILIZES A PAIR OF FORMING BELTS WITH ONE BELT HAVING HORIZONTAL AND VERTICAL RUNS AND THE SECOND BELT HAVING A VERTICAL RUN IN OPPOSITION TO THE VERTICAL RUN OF THE FIRST BELT AND DEFINING THEREWITH A VERTICALLY EXTENDING FORMING ZONE. PAPERMAKING STOCK IS DEPOSITED ON THE HORIZONTAL RUN OF THE FIRST BELT AND LIQUID DRAINS THEREFROM AS IT PROGRESSES TOWARDS THE VERTICAL FORMING ZONE. THE MAJOR PORTION OF THE STOCK MAKING   UP THE FINISHED WEB IS THEN DEPOSITED IN THE VERTICAL FORMING ZONE, WITH PRINCIPAL DRINAGE OF THIS STOCK DEPOSITION BEING THROUGH THE VERTICAL RUN OF THE SECOND BELT.

l- 1973 w. c. NOTBOHM 3,752,734

MULT I PLY PAPER MACH I Nl'l Filed Aug. 12, 1970 sf; I

INVE/VT'OR WILLARD C. NOTBOHM BY W M, wyfia ATTORNEYS United States Patent 3,752,734 MULTI-PLY PAPER MACHINE Willard C. Notbohm, Watertown, N.Y., assignor to The Black Clawson Company, Hamilton, Ohio Filed Aug. 12, 1970, Ser. No. 63,076 Int. Cl. D21f 11/04 US. Cl. 162-423 Claims ABSTRACT OF THE DISCLOSURE A multi-ply paper machine utilizes a pair of forming belts with one belt having horizontal and vertical runs and the second belt having a vertical run in opposition to the vertical run of the first belt and defining therewith a vertically extending forming zone. Papermaking stock is deposited on the horizontal run of the first belt and liquid drains therefrom as it progresses towards the vertical forming zone. The major portion of the stock making up the finished web is then deposited in the vertical forming zone, with principal drainage of this stock deposition being through the vertical run of the second belt.

BACKGROUND OF THE INVENTION It is fairly common in manufacturing heavier grades of paper and board to form the web as a multi-ply sheet through the use of multiple stock depositions. On a conventional papermaking machine of the fourdrinier type, the major or base layer of the stock is applied to the forming zone adjacent the upstream end of the wire, with a second, cover layer of appreciably less weight than the base layer applied at some point intermediate the breast and couch rolls of the machine. Due to the fact that the base layer has drained considerably and the fibers thereof felted out on the forming surface, drainage of the second layer is appreciably retarded, necessitating the use of a relatively long fourdrinier run.

A second approach to the manufacture of multi-ply webs utilizes a second forming wire having a substantially horizontal run positioned above a portion of the horizontal run of an otherwise conventional fourdrinier machine. In this type of operation, the base layer is again deposited at the upstream end of the fourdrinier machine with a portion of the liquid of suspension draining therefrom as it travels towards the downstream end of the machine. At a point downstream of the dry line, that is, the point at which visible moisture is no longer present in the sheet, additional stock is deposited on the partially felted base layer with drainage of this second layer taking place through both the top wire and the base layer. As a result, a dryer sheet is provided coming from the forming section than would be the case if all of the drainage of the second deposition had to take place through the partially felted base sheet and fourdrinier wire, but this type of construction is fairly expensive in that two forming wires are necessary as well as supporting structure for cantilevering the top wire over the portion of the fourdrinier which it opposes.

SUMMARY OF THE INVENTION The present invention utilizes a pair of endless foraminous forming belts with one belt supported such that it is formed with a horizontal run and a vertical run extending downwardly from the downstream end of the horizontal run. The second belt is supported to form a second vertical run positioned in closel spaced relationship to the vertical run of the first belt to define therewith a vertically extending forming zone.

The stock which will constitute the relatively lighter cover layer or layers of the finished sheet is applied to the horizontal run at one or more points therealong. Since Patented Aug. 14, I973 this portion will be a minor portion of the finished sheet, the horizontal run may be relatively short. At the upper end of the forming zone defined by the vertical reaches of the two belts, the major portion of the stock is deposited, thereby permitting the major portion of the dewatering to take place in the area where the greatest dewatering efficiency can be achieved, namely, the vertical run.

Thus as the stock is deposited in the forming zone defined by the stock covered surface of the vertical run of the first belt and the uncovered surface of the vertical run of the second belt, the liquid of the suspension of the second deposition will readily pass through the uncovered surface of the second belt. Of course, some continued dewatering of the first deposited layer will take place through the vertical run of the first belt as well as a portion of the liquid from the second stock deposition. However, principal drainage of the second stock deposition will take place, as noted, through the vertical run of the second belt.

As a result, it will be seen that not only is a dryer sheet obtained than with conventional fourdrinier machines, but the length of the belts, and hence the expense of the machine, may be decreased appreciably. Additionally, the relatively long belt runs necessary in the paper machines of the type utilizing an opposing top belt are decreased with the construction of the present invention as well as the necessity of a cantilevered support system for its upper belt.

BRIEF DESCRIPTION OF THE DRAWINGS The single figure is an elevational view showing a preferred arrangement of components for practicing the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT A papermaking machine according to the present invention comprises a first, endless, foraminous belt 10 supported by a pair of rolls 11 and 12 to provide a substantially horizontal drainage run 13. Rolls 11 and 12, which correspond to the breast and couch rolls, respectively, in a conventional fourdrinier type machine, are preferably of the suction type with each containing a suction device, as at 14 and 15, respectively. Additionally, belt 10, beneath the horizontal run 13 thereof, may be provided with a plurality of foils 16 and suction boxes 17 as Well as a tray 18 for collecting liquid draining from the stock deposited on the horizontal run 13.

A second belt 20 is supported by rolls 21, 22, 23 and 24 to provide a vertical run 25 thereof. Roll 24 in conjunction with roll 12 also serves to form a vertical run 26 of belt 10 which, in closely spaced relationship to vertical run 25, defines therewith a vertically extending forming zone 27. It will also be noted that within the loop formed by the second endless foraminous belt 20, dewatering equipment, which is shown somewhat schematically as a plurality of foils 28 and a collecting tray 29, but which may take the form of any convenient dewatering apparatus such as suction boxes and the like, is positioned for a purpose to be presently explained.

Adjacent the upstream end of the horizontal run 13*, a stock deposition device 30 is positioned for depositing a highly dilute suspension of papermaking fibers and liquid on the wire. While device 30 is illustrated as a pressure former, it will be apparent that the particular type utilized will be dependent upon the specific conditions of a particular installation. Downstream of the stock deposition device 30, a headbox 31 is positioned for adding an additional layer of dilute papermaking stock. Again, while device 3 1 is shown as a conventional headbox, it will be apparent that this may also be varied to suit the particular conditions of a specific installation. Moving to the downstream end of the horizontal run 13, it will be seen that at the upper end of the forming zone 27, a third headbox 32 is mounted for discharging papermaking stock into the forming zone 27.

In operation, a first layer of stock, forming, for example, 25% of the finished sheet, is deposited by the stock deposition device 30. Liquid from this stock drains through the foraminous belt 10 at the horizontal run 13 thereof assisted by foils 16 or any other dewatering equipment. At a point downstream from the roll 11, preferably in most installations at a point downstream of the dry line of the horizontal run 13, an additional layer of stock is deposited by the headbox 31. This layer, which may comprise approximately 10% of the finished sheet, is deposited on the horizontal run with drainage thereof being assisted by the suction boxes -17. At the upstream end of the forming zone 27, the stock for the major portion of the finished sheet, for example, approximately 65% thereof, is deposited, with the principal drainage taking place through the vertical run 25- of the second foraminous belt 20 assisted by the foils 28 or other dewatering equipment.

Thus, the relatively low amount of drainage necessary for the first two layers applied takes place through the horizontal run 13 which may, therefore, be kept relatively short. The major portion of the drainage from the web takes place through the vertical run 25- of the second foraminous belt 20, that is, at the point where the greatest dewatering efficiency is encountered. It will also be seen that only a relatively minor portion of the dewatering of the last deposited stock takes place through the previously felted fibers covering the surface of the vertical run 26 of the first foraminous belt 10. As a result, not only is dewatering efiiciency increased appreciably, but the danger of disturbing the formation of the first deposited layers of stock is decreased. Of course, although three stock deposition devices are shown, it will be apparent that only two or more than three could be utilized.

From the turning roll 24 the first foraminous belt 10 is trained about a suction roll 33' and thence around turning rolls 34, 35 and 36. A suction pick-up roll 40 covered by pick-up felt 41 serves to transfer the web from belt 10 to the press section of the papermaking machine.

From the above it will be apparent that the present invention provides a highly efficient method and apparatus for making multi-ply paper and board with relatively short forming belts and highly efficient dewatering with a minimum disturbance of the previously felted stock.

While the method herein described, and the form of apparatus for carrying this method into effect, constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A multi-ply paper machine comprising:

(a) a first endless foraminous belt forming a closed loop,

(b) pair of spaced, horizontally aligned rolls positioned within said loop with the portion of said belt extending between said rolls defining a horizontal run,

() a second endless foraminous belt forming a closed loop,

(d) a pair of vertically aligned rolls positioned within said loop of said second belt with the portion of said second belt extending between said vertically aligned rolls defining a vertical run,

(e) an upper one of said vertically aligned rolls lying in substantially the same plane as said horizontally aligned rolls in closely spaced parallel relationship to one of said horizontally aligned rolls,

(f) a portion of said first endless belt wrapping the lower one of said vertically aligned rolls and defining a vertical run of said first belt extending from said one of said horizontally aligned rolls to said lower one of said vertically aligned rolls,

(g) a plurality of stock deposition devices positioned adjacent to said horizontal run,

(h) an additional stock deposition device positioned adjacent and intermediate said one of said horizontally aligned rolls and said upper one of said vertically aligned rolls,

(i) said vertical runs of said first and second belts defining a forming zone for stock deposited therein by said additional stock deposition device,

(j) said additional stock depositing device constituting substantially the only source of stock deposition on said second wire with said second wire being free of further stock deposition devices upstream of said additional stock deposition device whereby substantially all of said stock deposited in said forming zone can drain through said second wire.

2. A method of forming a multi-ply web on a paper machine which includes a first endless foraminous belt supported to define a horizontal run and a vertical run extending downwardly from a downstream end of said horizontal run and a second endless foraminous belt supported to define a vertical run positioned in closely spaced relationship to said vertical run of said first belt comprising:

(a) depositing a dilute suspension of papermaking fibers on said horizontal run of said first belt,

(b) draining a substantial portion of the liquid of said suspension through said horizontal run of said first belt,

(0) maintaining said second belt substantially free of fibrous material upstream of said vertical run thereof,

(d) depositing a dilute suspension of papermaking fibers between said vertical runs of said belts adjacent the upper ends thereof, and

(e) draining a substantial portion of the liquid of said suspension through said vertical run of said second belt and a relatively less amount through said vertical run of said first belt.

3. The method of claim 2 wherein said step of depositing a suspension of papermaking fibers between said vertical runs comprises:

(a) depositing in excess of more than half the total fibers for the finished web between said vertical runs.

4. The method of claim 3 wherein said step of depositing a dilute suspension of papermaking fibers on said horizontal run comprises:

(a) depositing said suspension at a plurality of points along said horizontal run.

5. The method of claim 4 wherein said step of depositing said suspension at a plurality of points along said horizontal run comprises:

(a) depositing fibers equal to approximately 10% of the total fibers of the finished web at one of said points.

6. The method of claim 5 wherein said step of depositing a suspension of papermaking fibers between said vertical runs comprises:

(a) depositing approximately 65% of the total fibers of the finished web between said vertical runs.

7. A multi-ply paper machine comprising:

(a) a first endless foraminous belt forming a closed loop,

(b) support means positioned within the loop of said first belt in supporting relationship thereto and defining a pair of drainage runs,

(0) each of said drainage runs of said first belt having upstream and downstream ends and being angularly disposed with respect to each other with the upstream end of one of said drainage runs substantially coincident with the downstream end of the other of said drainage runs,

(d) a second endless foraminous belt forming a closed loop,

(e) support means positioned within the loop of said second belt in supporting relationship thereto and defining a drainage run having upstream and downstream ends,

(f) said drainage run of said second belt and said one of said drainage runs of said first belt extending in closely spaced relationship to each other and defining a forming zone having upstream and downstream ends,

(g) first means for depositing papermaking stock on said other of said drainage runs of said first belt adjacent the upstream end thereof,

(h) second means for depositing stock into said forming zone at said upstream end thereof,

(i) said second stock depositing means being substantially the only stock depositing means associated with said second belt whereby said second belt approaches said forming zone substantially free of fibrous material and a major portion of stock deposited by said second stock depositing means drains through said drainage run of said second belt.

8. The paper machine of claim 7 wherein:

(a) each of said drainage runs is substantially planar.

9. The paper machine of claim 7 wherein:

(a) said one of said drainage runs of said first belt and said drainage run of said second belt are sub stantially vertically oriented, and

(b) said other of said drainage runs of said first belt is substantially horizontally oriented.

10. The paper machine of claim 7 further comprising:

(a) additional stock deposition means for depositing paper making stock on said other of said drainage runs of said first belt.

References Cited UNITED STATES PATENTS 1,718,574- 6/ 1929 Millspaugh 162F303 X 3,149,028 9/ l964 Robinson 162203 X 1,748,360 2/ 1930 Millspaugh 162-268 X 2,286,942 6/11942 Tuten 1'62123 1,018,588 2/ 19 12 Scanlan 16Z304 3,471,367 10/1969 Chupka 162-123 X 2,881,672 4/ 1959 Thomas 162.299 X FOREIGN PATENTS 1,904,962 8/ 1970 Germany.

S. LEON BASHORE, Primary Examiner 25 R. H. TUSHIN, Assistant Examiner US. Cl. X.R. 

